1. Field of the Invention
The invention relates to the use of N-(tetrazol-4-yl)- or N-(triazol-3-yl)arylcarboxamides or their for controlling unwanted plants in areas of transgenic crop plants being tolerant to HPPD inhibitor herbicides.
2. Description of Related Art
EP 10174893 (being filed in the name of Bayer CropScience AG at the EPO on Sep. 1, 2010) and its corresponding international application PCT/EP2011/064820 disclose several new N-(tetrazol-4-yl)- or N-(triazol-3-yl)arylcarboxamides and their use as HPPD inhibitor herbicides for weed control.
However, the herbicidal activity of N-(tetrazol-4-yl)- or N-(triazol-3-yl)arylcarboxamides might cause damages on several crop plants which limit their use in such crop growing areas as herbicides for weed control.
HPPD inhibitor herbicides can be used against grass and/or broad leaf weeds in crop plants that display metabolic tolerance, such as maize (Zea mays) in which they are rapidly degraded (Schulz et al., (1993). FEBS letters, 318, 162-166; Mitchell et al., (2001) Pest Management Science, Vol 57, 120-128; Garcia et al., (2000) Biochem., 39, 7501-7507; Pallett et al., (2001) Pest Management Science, Vol 57, 133-142). In order to extend the scope of these HPPD inhibitor herbicides, several efforts have been developed in order to confer to plants, particularly plants without or with an underperforming metabolic tolerance, a tolerance level acceptable under agronomic field conditions.
Meanwhile transgeninc plants have been engineered by by-passing HPPD-mediated production of homogentisate (U.S. Pat. No. 6,812,010), overexpressing the sensitive enzyme so as to produce quantities of the target enzyme in the plant which are sufficient in relation to the herbicide has been performed (WO96/38567).
Alternatively, transgenic plants have been generated expressing HPPD proteins that have been mutated at various positions in order to obtain a target enzyme which, while retaining its properties of catalysing the transformation of HPP into homogentisate, is less sensitive to HPPD inhibitor herbicides than is the native HPPD before mutation (for example see at EP496630, WO 99/24585).
More recently, the introduction of a Pseudomonas HPPD gene into the plastid genome of tobacco and soybean has shown to be more effective than nuclear transformation, conferring even tolerance to post-emergence application of at least one HPPD inhibitor (Dufourmantel et al., 2007, Plant Biotechnol J. 5(1):118-33).
In WO 2009/144079, a nucleic acid sequence encoding a mutated hydroxyphenylpyruvate dioxygenase (HPPD) at position 336 of the Pseudomonas fluorescens HPPD protein and its use for obtaining plants which are tolerant to HPPD inhibitor herbicides is disclosed.
In WO 04/024928, the inventors have sought to increase the prenylquinone biosynthesis (e.g., synthesis of plastoquinones, tocopherols) in the cells of plants by increasing the flux of the HPP precursor into the cells of these plants. This has been done by connecting the synthesis of said precursor to the “shikimate” pathway by overexpression of the prephenate-dehydrogenase (PDH). They have also noted that the transformation of plants with a gene encoding a PDH enzyme makes it possible to increase the tolerance of said plants to HPPD inhibitors.
In WO 2002/046387, an gene obtained from Avena sativa encoding an HPPD was described to generate plants overexpressing such gene and thereby causing tolerance to various HPPD-inhibitor herbicides.
In WO 2008/150473, the combination of two distinct tolerance mechanisms—a modified Avena sativa gene coding for a mutant HPPD enzyme and a CYP450 Maize monooxygenase (nsf1 gene)—was exemplified in order to obtain an improved tolerance to HPPD inhibitor herbicides, but no data have been disclosed demonstrating the synergistic effects based on the combination of both proteins.
In WO 2010/085705, several mutants of the Avena sativa HPPD were described as well as plants comprising genes encoding such mutated HPPD and thereby causing an increased tolerance to various HPPD-inhibitor herbicides compared to non-mutated HPPD.
Recently, several new genes encoding HPPD enzymes from various organisms have been identified and employed for obtaining crop plants that show an agronomically useful level of tolerance concerning the application of various HPPD inhibitor herbicides.
The work concerning the implementation of such tolerance against HPPD inhibitor herbicides have extensively been described in the PCT-applications being filed in the name of Bayer CropScience AG on Dec. 22, 2010, having the filing numbers (PCT/EP2010/070561 (published as WO 2011/076877; relates to nucleic acid sequences encoding a hydroxyphenylpyruvate dioxygenase (HPPD) obtained from bacteria belonging to the subfamily Synechococcoideae and certain mutants thereof); PCT/EP2010/070567 (published as WO 2011/076882; encoding a hydroxyphenylpyruvate dioxygenase obtained from protists belonging to the family Blepharismidae); PCT/EP2010/070578 (published as WO 2011/076892; encoding a hydroxyphenylpyruvate dioxygenase obtained from bacteria belonging to the genus Rhodococcus and certain mutants thereof); PCT/EP2010/070570 (published as WO 2011/076885; encoding a hydroxyphenylpyruvate dioxygenase obtained from Euryarchaeota belonging to the family Picrophilaceae and certain mutants thereof); PCT/EP2010/070575 (published as WO 2011/076889; encoding a hydroxyphenylpyruvate dioxygenase obtained from bacteria belonging to the genus Kordia and certain mutants thereof) and which are hereby incorporated by reference concerning the production of the respective transgenic plants conferring tolerance to HPPD inhibitor heribicides.